Together with marine biologist Uli Kunz we explore the North and Baltic Sea and show that these supposedly well-known seas have a lot of surprises in store. In the east of Finland we follow the largest animal migration in Europe – with the reindeer and their herdsmen we go out onto the frozen Baltic Sea. We experience the importance of the coasts for bird migration and accompany scientists to Helgoland to explore the underwater world. We encounter grey seals and harbour seals – and learn how the North Sea and Baltic Sea were formed thousands of years ago.